This research paper examines the impact of tax evasion on the world economy. Tax evasion constitutes an illegal act of avoiding obligations required by the state tax laws. The causes of tax evasion can be classified into three groups, namely: issues of institutional infrastructure, legal system and social and economic causes. Talking about the ways of assessing tax evasion, it can be estimated by direct and indirect methods as well as by causal models. Tax evasion appears in several forms. As a lawful tax evasion, which can be intended and unintended, and as an unlawful tax evasion in the form of evading, defrauding and smuggling. The impact of globalization is also noticeable in economic flows worldwide. National economies are faced with certain negative effects of globalization. The consequences can be noticed in the area of taxation, where tax evasion, double taxation and tax competition arise. The appearance of tax havens is closely related to tax evasion. Tax havens are areas with no or low tax rates whose benefits are used by large multinational corporations as well as individuals. According to the OECD there are 38 states in the world that are considered to be tax havens. The impacts of tax havens are noticeable when it comes to the flow of money in the world, direct foreign investments, but also the global wealth of households that is hidden in tax havens. EU countries are struggling with the gray economy although, in the share of the GDP of EU member states, it has declined from 2003. to 2015.